Torque overload release device



May 4, 1948.

wonqun OVERLOAD RELEASE DEVICE Filed Au 18, 1945 VII/III,

INVENTOR Wliam M 366861 mofi i I 'w. MJSIESEL 2,441,038

Patented May 4, 1948 deer-cs TORQUE oyEnL'oAn RELnAs DEvren William Ml Siesel;-Morrisviile; Pai; Josephine M; Siesel-executrixofsaid WilliamzM: Siesel, de-

ceased AppllcatiqnAhgustB, 1943; SerialNo; 495L061 4 Claims; 1:.

The" present invention relates to an improve ment in torque overload release-devices One object thereof-hasbeentoprovidea more rug ed and durable tool for the purpose-and' one which is simple and economical to manufacture. A further object has been'to provide'in'such a device, means-'- whereby the torque overload 'releasing capacity thereof may be adjusted or set toany desired degree-or pointwithir'ra wide range, or to any predetermined point tlierein'; as byreference to a set of markings; Another oh ject is to pr-ovide a device"ofdiinensions' sosmall that it can be encompassed in the'handle or: body of a tool of ordinary size.

One embodiment of"my= lnvention as applied to the cons truetion of a: hand 'tool of the wrench or screw driver type, is described inthe' following specification and illustrated in the attached drawings wherein- Figure 1 is a view in elevation w-ith -uter" por'- tions broken away and" inner portions shown partly-in central longitudinal seetion;

Figure. 2, atransverse sectionzomthe line 2 --2 of Figure' 1 Figure 3, a I transverse section ou -the line 3 3 OfIFigure 1 Figure 4, a view in lon'gitudinaliseetion of 'a'n other embodiment of 5 my invention; Fan a l Figure 5; a" cross sectional "viewtaken on the line 5'+5 'ofFigure '4;

Referring tothe': drawings a tool raccording 'to my invention includsidrivingemeans and driven means and, in i effect; -a.' =S1l'pi'bl'a11SmlSSiOi1i which may be adjustedlto operate up:o?-any predeter mined torque overload within theelimits'fornvhlch' the toolis designed Likewise; thefpartsfateither side of the transmissi-on'areereversrblerfin functi'on in :thatthe driven meansmayzbe: employed asethe driver and vice. versa;-

Where'the tool embodying'the invention isza wrench, as shown in Figure liforfexample; the driving; means forthatipnrpose includes a handle I having a central longitudinal recess 2. At the inner end of said recess-ris a washer 3 having a centrally located protrusionsfin An'detent member, shown as a ring 5; is fiiredihtheinner end of said recess 2 with one edge seated against Washer 3. The interiorsurface'ofsaid' ring 5 is provided with longitudinal grooves 6 which,= with the. ridges between them, form rm efiectcorrugated or irregular bearingesu-riace arranged to engage bearing portions of th odriven meanss The driven means, as showm.ineludesaewrench having a, head"! and a shanl; 8, said shank having a longitudinal'V-shapeclgroove 9, which receiveszthe inner end of asetiscrew I0 when tshank 8 -'-is:operatively assembled .WithT-afiGOllGt having a peripheral groove I2.

As seen in Figure 2, the inner end of collet II is divided into four parallel segments or arms I 3 videispaced outwardly arranged' around the central bore of the collet which made of such material; steel for 6X4 ample, as? will impart "a resilient or springy qual or ridge-dike hearings to' engage said bearing surface's'of: ringrfi'. Each ofthe free ends of said arms: .I3,-.inthe embodiment shown, is provided with azlongitudinally extending recess I4which holds aroller bearing I5. Said recesses open through end surf-acesfof, said arms and also through outwardly exposed lateral surfaces thereof: so that whenthe roller bearings. I-5 are mountedtherein, as shown, peripheral 5 portions of said bearings form ineffect. ridge-like protuberan ces' whichproject beyond said outer latoral-surfaces: e

The; cjollet H is retained in the means of. pins" 6. extending across-portions, of saidiperiphera-l groove I2, so that said'collet-is free to rotate butis locked by said pins against endwise' displacement. When assembled; with ring fi; the angularlyspaced bearings, as rollers 1-5; carried by said collet normally yieldinglyem gage the adjacent groovesfi. X e

The central-bore of said col-letis of reduced diametenat its end portion adjacent the rollers 1 thus forming a shoulder Hon each-arm l3 against wh'ich the inner-end of shank 8 is seated at-oneextrerne position of adjnstmentthereofi Said shank-maybe moved alongthe bore of said cnlletto any other-desired position of adjustment in relation to the iree endsycf said arms I 3-: and secured in such position by set-screw Ill;

I nioperatingrthe above describedstructure as a wrench, rotation ofrthe handle I will be imparted toacollect IJI andthence-to shank 8 through the rollers I5, or other suitable projecting bearing portion or: said arms I3, until theiresistance-be- 'comes-sueh-that said arms I3 are flex-ediinwar-dortoiizardcenter,by the ridges of detent-ring 5 which then rideor slip over the engaged surfaces ofvrollersJ 5. r e I When shank-Bis adjusted with its inner end seated 'against shoulders I (of arms 13'; the parts arersubstantiallylocked so that no yield occurs in nom alluse.- Saidshankdmaybe moved to and from any, desired or predetermined position of adjustment towary the efictive length of said arms'and thus Vary. their spring characteristics or torque overload releasing capacity, but should handle I .loy

ordinarily allow a substantial spring, arm length beyond the-end of the shanks. A range or-nor: ma] adjustments is indicated b'y' 'the fiducial markings, a, b, c, d, e and f, forexampl'e; The roper arm length :for any given torqueis. determined. by, the section modulus of the'spring. 'a'rm' used and loythe material used.

It will'be apparent" that, for some purposes; equivalent efiects may be obtained in use with a torque release device having certain of the parts inverted. For example, the corrugated or irregular bearing surface may be outwardly exposed and the bearings on the spring arms may extend inwardly to ride thereon. In such case, adjustment of the spring characteristics of said arms as by varying their effective length, may be made by a sleeve, or the like, embracing portions of said arms, or, as shown in Figure 4, the sleeve may be slidable with respect to the spring arms to contact closer or farther from their tied ends.

One advantage of the construction embodying my invention is that it is so compact as to be readily embodied in numerous types of existing structures. Its application to screw drivers and so-called spiral or Yankee" screw drivers and the like is obvious from what has been said above. It is applicable in power tools and special power drivesas well as in handtools.

A further advantage of the above described structure over previously known devices for a similar purpose is that the use therein of rollers, or other extended bearing members instead of ball bearings, for example, reduces the tendency to roll down the detent surfaces and thus alter the torque transmitting factor of the device as a whole.

As shown in Figures 4 and 5 a socket wrench or screw driver, or Yankee drill is provided with a shank 8a squared or of any other desired noncircular cross-section. Slidably mounted on this shaft is a sleeve or ring 5a provided with longitudinal grooves 641 on its external surface and having its central opening fitted to the shank 8a. A set screw illa serves to secure the sleeve or ring 5a in any desired longitudinal position along shank Ba in order to use a longer or shorter effective spring arm length. Spring strips 13a are bent to U-form as shown and overlapped in perpendicular position. The extended side arms of these spring members arealso bent in cross-section to present a convex inner face for engagement with the grooves 6a in the ring 5a. and are suitably hardened to provide the desired spring and resistance to wear. These overlapped spring members are received and engaged in the cruciform opening at the upper end of the handle as most clearly shown in Figure 5 and the assembly is held together by the screw 20.

In the use of this device, the torque is transmitted from the handle la through the spring arms Ba and the grooved ring in to the shank 8a and through it to the actual tool. If, however, the torque supplied exceeds a predetermined maximum load, the spring arms 13a are cammed out by the ring in. and the handle thereafter turns relative to the shank 8a.

The device of the present invention also affords advantages over others of known types in that-its torque overload release factor supplied by the spring arms of the collet remains substantially constant whereas, coiled springs, or the like, may tend to vary with repeated use. Furthermore, the above described construction whereby torque release adjustment is effected involves a minimum of parts; and calibrations for predetermined values of torque release can be readily and accurately made and relied on.

What I claim is:

1. A torque overload release device comprising a driving member and a driven member, one of said members including a collet having a head portion and a longitudinally slit portion extendshank with respect ing in coaxial relation from said head portion, with a. central bore substantially uniform in cross-section throughout a substantial portion of the length of said slit portion when in operative relation, and the other of said members including a detent ring, said detent ring and at least one free end portion oi" said collet being provided one with at least one protuberance and the other with cooperating surface having at least one re- .cess from true circular form for each protuberance and adapted to receive said protuberance therein, said members being assembled with such protuberance yieldingly engaging said recessed surface, a shank slidably fitted in the bore of said collet, thereby supporting against inward flexing the adjoining portions of the collet, and means for securing said shank in various positions of longitudinal adjustment in relation to said collet.

2. A torque overload release device comprising a driving member and a driven member, one of said members including a collet having a head portion and a slit portion forming angularly spaced segmental arms extending in parallel relation from said head portion with a central bore extending therethrough of substantially uniform cross-section throughout a substantial portion of its length when in operative relation and with protuberant bearing faces on free end portions of said segmental arms, and the other of said members includinga detent provided with an annular bearing engaging surface with recesses at angular spacing corresponding to the spacing of said protuberant faces, said members being assembled with said protuberant bearing faces yieldinglyengaging in said recesses of the detent, and a shank telescoped closely into said bore whereby to support adjoining portions of said segmental arms against inward flexing and adjustable in relation thereto to vary the torque release controlling effect of said arms as transmitted through said bearings.

3. A torque overload release device as defined in claim 2 wherein the shank is provided with an indicating scale whereby the torque transmissible thereby is indicated by the axial position of said to said bore and said device'further comprises means for releasably securing said shank at any of a substantial range of telescope positions.

4. "A tool which comprises a hollow handle, the torque overload release device as defined in claim 1 telescoped into said handle with the detent secured thereto and said collet rotatable therein and operative tool means secured to the outer end of said shank.

. WILLIAM M. SIESEL.

REFERENCES CITED The following references are of record in the file of this "patent:

UNITED STATES PATENTS 

